Ship salvaging apparatus



Feb. 10, i942. c. M. ZOLL 2,272,785

SHIP SALVAGING APPARATUS Feb. 10, 1942. C, M, ZOLL 2,272,785

SHIP SALVAGING APPARATUS Filed April 25, 1941 4 Sheets-Sheet 2 Feb. l0,1942. Q M ZOLL 2,272,785

SHIl'j SALVAGING APPARATUS Filed April 25, 1941 4 SheetS-Sheei 3 .Hlm

Feb. 10, 1942. c. M. ZOLL SHIP SALVAGING APPARATUS Filed April 23, 19414 Sheets-Sheet 4 Patented Feb. l0, 1942 Carl M. Zoll, Dundalk, Md.,assigner to Universal Hydraulic Stress Equalizer, Inc., Dundalk, Md.

Application April 23, 1941, Serial No. 389,974

21 claims.

This invention relates to ship salvaging apparatus for raising sunkenships.

It is a common practice in raising. sunken vessels to sink water lledpontoons alongside the ship, secure them thereto by chains vpassed underthe ship and blow out the water with compressed air. The buoyancy of thepontoons is then supposed to be utilized to'raise the ship. `Such aprocess requires much under-water work on the part of divers inpositioning and securing the pontoons in place and it is extremelydiiiicul't to so position the pontoons that the sunken ship will riseevenly. In fact experience has shown that one end of such a ship willbreak free from the bottomvwhile the other end is still held by the mudor sand and the pontoons will slip od the risen end. Further, if thesunken ship be lying on her side it will be practically impossible bythis method to restore her to an even keel position so that, even ifsuccessful shewill be brought to the surface on her side as shelay onvthe bottom.

One important object of the invention is to provide a novel apparatuswhereby a sunken ship may be raised with a minimum of work by divers.

A second important object of the inventionis to provide novel salvagingmeans whereby it will be possible to raise a sunkenvship without theemployment of pontoons.

A third important object of the 'invention is to provide a novelsalvaging apparatus whereby a sunken ship may be raised on an even keeleven though lying on its side in sunken position.

A fourth important object of the invention is to provide a novelsalvaging apparatus whereby the hoisting of a sunken ship will not beaffected by storms of any ordinary intensity.

A fifth important object of the invention is to provide a novelsalvaging apparatus including hoisting means attachable at spaced pointson each side of the sunken ship and wherein even and equal stresses willbe maintained on all the hoisting means independently of wave action.

A sixth important object of the invention is to provide a novelsalvaging apparatus wherein hydraulic means are -used to equalize theweight of the sunken ship at various points in its length.

A seventh important object of the invention is to provide such asalvaging apparatus having hoist supporting girders carried by barges oriioats and maintained at a uniform position in space independently ofweather and sea conditions. L

An eighth .important object of the invention is in the apparatus may bereadily adjusted for any length and beam measurements of a sunken shipWithin the upper limit of tonnage and size of ship the apparatus isdesigned toraise.

A ninth important object of the invention is to provide an apparatus ofnovel construction wherein the major parts may be readily assembled foruse and disassembled for movement from one place to another.

With the above and other objects in view, theinvention consists ingeneral of certain novel details of construction and combinations ofparts hereinafter fully described, illustrated in the accompanyingdrawings and particularly pointed out the appended claims.

In the 'accompanying drawings like characters of reference indicate likeparts in the several views, and:

Figure l is an end elevation to small scale ofl the complete apparatuswith the two barges forming the supports for'the remainder of thelapparatus at the same level. Figure 2 is a. view similar to Figure 1 butwith the barges at different levelsv and certam parts omitted.

Figure 3 is a plan view showing the apparatus in position for raising asunken vessel, the latter being indicated by broken lines.

Figure 4 is an enlarged fragmentary section on the line @-6 "of Figure3.

Figure 5= is a similar section on the line 5-5 of Figure 3. y

Figure 6 is a further enlarged section on the line 6 6 of Figure 4.

Figure 7 is a plan view of one of the weight supporting cylinders usedin this device.

Figure 8 is a section on the line 8-8 of Figure 7.

Figure 9.is a section on the line 9-9 of Figure 6.

Figure 10 is a plan view of one of the balancing cylinders used in thisdevice.

Figure 11 is a section on the line lI-'|I of Figure 10.

Figure 12 is an enlarged detail section on the line |2--I2 of Figure 2.f

Figure 13 is a side v elevation of the detail shown inFigure 12.

Figure 14 is a side elevation of a portion of an equalizer device.suitable for use herein.

Figure 15 is a fragmentary section through one end portion of the deviceshown in Figure 14.

The structure as disclosed in the present drawings includes in general apair of barges or iloats to provide a novel'apparatus' of thisclasswhere- 55 F each carrying a set of tower structures T. The

towers T of onel barge are connected to corre- 4sponding towers of theother barge byhoisting self propelled or they may be moved from place toplace by tugs or the like.

The towers T are spaced longitudinally of the respective barge and maybe as many as desired from two up. Preferably the spacing between,centers of the towers is uniform. All the towers are of likeconstruction and each includes a base IIJ whereon is suitably mounted aturntable or platform II the periphery of which constitutes a worm gearengaged by a worm I2 actuated by a' motor I3. The motor I3 may be of anysuitable kind but is preferably an electric motor obtaining its powerfrom a suitable source (not shown) which may be an electric generatingplant carried bythe barge or may be brought on board through an electriccable from a mother ship. By this means the towers may be rotated if andwhen desired. Mounted on each platform II is a structural steel framehaving vertical corner posts and inclined braces indicated as at I4. Asquare frame I5 holds the uprights and braces in proper relation at thetop of each tower. n each platform II is a winding drum I6 actuated by asuitable motor l1. Above .the winding drum and its motor is a lowertower deck I8 and spaced between the deck I8 and frame I5 is an uppertower deck I9. Between the frame I and deck I9 on those sides of thetower which normally constitute the forward and after sides is a pair ofvertical-guides 20 and between each pair of these guides fits a guidebar 2| fixed on one side of a carriage or housing 22 which may thusslide vertically of the tower. Rollers 23 serve to engage the guides torender easy the up and down movement of the carriage and to preventjamming of the latter under twisting stresses which may be induced byrocking of the barge. These rollers are omitted from Figures 1 and 2because of the small scale of those figures.

Each of the bridges or girders B is here shown as consisting of threeI-beams 24 but it is to l e understood that any desired construction ifgirder may be used and that the. constructirn will vary bothin form andsize in accordance with the maximum dimensions and weight of vessel theparticular embodiment of this invention is designed to salvage. Thebeams 24 may be connected to form a unitary girder by any preferredmeans as here indicated in Figures 12 and 13 at 25. Also these girdersmay be formed in two or more sectionsreleasably secured together as byfish plates 26. Each girder has one end slidably mounted in the carriage22 of. one tower of a barge and its other end slidably mounted in thecarriage 22 of the corresponding tower on the other or second barge.Thus the barges may be adJusted to anysuitable distance apart within thelimits determined by the lengths of the girders.

It is intended that normally the carriage 22 shall lle, when the weightof the sunken ship S is fully supported on the apparatus by the meanspresently to be described, about half way between the frame I5 and upperdeck I9 and to the end there is mounted on the deck I8 beneath thecentral beam 2l a cylinder 21 which extends up to deck I9 and in thatdeck is an openingso that a plunger 28 tightly fitting the cylinder 21may extend through this deck. The plunger 28 is provided with a head 29carrying a roller 38 engaging against the under side of the carriage 22.Also fixed on the deck I8 is a pressure chamber 3| and the lower ends ofthe cylinders 3I and 21 are connected by a nipple 32a. The lower part ofthe cylinder 3l constitutes a hydraulicv portion, being lled preferablywith a suitable oil which also fills all of the cylinder 21 below theplunger 28. The upper part of the cylinder 3I constitutes a compressedair chamber 32, being iilled to the desired pressure through a valvedpipe 33. While the air in the chamber 32 may exert pressure directly onthe oil below it is preferred to interpose a floating piston 34 providedwith air tight packing 35 between the oil and air. With the arrangementshown, these pistons equalize the load in case one side of the sunkenship,is heavier than the other, the air pressure on the heavier sidebeing greater than that on the lighter side.

Also, on each deck I8 there is provided a pair of stress equalizingcylinders 36 aligned below the lateral beams 24. These cylinders arearranged like the cylinder 21 and are each provided with a piston 31having a head 38 carrying a roller 39 which engages beneath the carriage22. Pipes 48 connect the cylinders of the several towers of the barge,each pipe being provided with valves 4I so that any cylinder may beisolated for repairs or if the conditions are such that its use is\notnecessary or desirable. plunger has an oil duct 43 leading from itsbottom end to a point adjacent its top where it is provided with alateral outlet 44 to which is fitted one end of a pipe 45, which leadsby suitable bends to a point within the tower and'above the girder B.There are thus two pipes 45-for each tower and the pipes of each toweron one barge are connected tothe pipes 45 of the corresponding tower onthe other barge through transverse pipes 46 provided with flexible orother expansion joints 41 to absorb the variations of the space betweenthe towers caused by rollingy or other movement of the barges. By thearrangement of the Ipipes 40 and 46 the pressure up-v wardly on thepistons 31 will ybe equalized under all conditions of operation. Forexample, if, as shown in,.Figure 2, the left hand barge is raised bywave motion higher than the right hand barge the rise in the oil levelin the left hand cylinders which would take place were the cylinders notconnected from one barge to the other is immediately counter-balanced byflow through the pipes 48 so that the levels of -the bottoms of thepistons 31 and consequently the bridges or girders will remain at theiroriginal. levels. The same compensation in level is obtained underpitching of the barges. through the pipes 4l) and through both sets ofpipes under any working conditions of combined pitching and rolling.

In order to overcome or check any variations in the longitudinalpositions of the girdersin the towers each girder has attached to eachside a pair of aligned dash-pot cylinders 48 provided with pistons 49'abutting against a center plate 50 xed in the carriage 22. Thesecylinders 48 thus constitute a species of air cushions to resistmovement ofthe girder. In order that the girder may be adjusted whendesired the girder is provided Each are more fully shown in Figures 12and 13. The

upper block of this tackle comprises a body member 53 resting on thelower flanges oi the beams 24 and secured in desired position by bolts 54 passing through selected ones of the spaced bolt holes. The body 53supports a plurality of sheaves number of sheaves to suit the numbercarried by the body 53. The hoisting cable 58 is led around thesesheaves and to the winding drum 56 and the lower block 51 also carriesaas indicated at 15. In another manner of posi'- tioning the barges theymay be moved individually into position, connected by the cables 14; andmoored. The girders, are then assembled with the towers. When the bargesare in position the hoists or tackles are attached to the sunken ship. V

by divers if the ship is entirely submeregd. The hoistingnirums are thenmanipulated to. take up the slackl on the cables. The air chambershavingbeen chargedv to the desired pressure, to equalize possible diierence inweight of the two sides of the ship, the bridges will be in proper ynormal height and the hoisting of the sunken I6. In its passage tol thedrum the cable is led under an idler sheave 59 carried by a lever 60which is pivoted tothe tower at 6l. This lever is connected to thecarriage 22 by a rigid link 52 as by suitable pivot connections atv eachend of the link. The purpose of this arrangement is to preventundesirable changes in the tension of the hoisting cables. The manner inwhich this is eiected will be best understood .by observation ofFigure2. If it were not for this arrangement the lift of the left hand barge,the girder B remaining constantly in position in space, would shortenthe distance between the winding drum I6 and upper blockl with aconsequent slackening of the cable. However, the lift i of the bargecauses the lever 60 to swing `down with respect to the drum I6 and theaction of the idler thus takes up the slack. Similarly the drop of theright hand barge increases the dis "tance between the drum I6 and upperblock, but the lever 60 swings up at the same time and thus lessens theangularity of the parts of the cable at opposite sides of the idler and,in eiect, lengthens the cable in accordance with the drop.

'Ihe towers 4on each barge may be connected by overhead bridges 63removably suppcrtedon brackets 64 carried by the towers.

It may, in some cases be desired to spread the supporting arca along thelength of the sunken.

ship at one. or more towers and to that end an equalizer E may be hungfrom a lower block 51.

One such equalizer is shown in Figures 14 and 15.

In this form a row of upper sheaves 65 are carried by bolts 66 whichextend between bars 61.

Lower blocks 68 carrying hooks 69 are arranged f below these bars and acable 69a is led over these upper and lower sheaves and anchored tobolts 10. A yoke bar 1| of inverted V-shape has its ends secured bybolts 12.

In order to facilitate assembling and disassembling of the girders inrelation to the towers an ordinary jib-crane 13 may be. mounted on eachtower by which the girder sections may be separated and each sectionwithdrawn from its tower and lowered onto the deck of the barge or thebarges may be moved apart, while the cranes support the girderends,until these ends'areclear ship may proceed. When the ship has beenraised to a desired height the repair work may proceed to enable theship to be pumped out and floated, such repairs andv pumping takingplace where the ship was sunk or the barges and suspended ship may bemoved bodily to any convenient place for such work. If thesuperstructure of the sunken ship is, when the latter is raised, indanger of fouling the bridges the amount of fluid in cylinders 36 may beincreased whereupon the bridges may be moved toward the tops of thetowers by the upward movement of pistons 31 to maximum height.

`What is claimed, is:

1. In a ship salvaging apparatus, spaced iioatation means, elevatedgirders spanning the space between the` fioatation means, ship hoisting'supported from the iloatation means and maintaining the girders atconstant heights above the horizon of a bo'dy of water supporting saidiioata tion means independently of vertical movements of the oatationmeans.

2. In a ship salvaging apparatus, spaced iiloata-V tion means, elevatedgirders spanning the space between the oatation means, ship hoistingmeans carried by saidsgirders, and leveling means supported from theoatation means and maintaining the girders at constant heights above-thehorizon of a body of water supporting said floatation meansindependently of vertical movements of the oatation means, said levelingmeans including hydraulic pressure elements supporting each end of therespective girders and piping connecting the pressure elements. I

3. In a ship salvaging apparatus, spaced oatation means, elevatedgirders spanning the spacebetween the oatation means, shipdhoistingmeans carried by said girders, and leveling means supported from theoatation means and maintaining the girders at constant heights above thehorizon of a body of water supporting said floatation meansindependently of vvertical movements kof the oatation means,y saidlevelingmeans including hydraulic pressure eleof the towers when thebarges may be moved together and the entire girder swung around to lieon the deck of one barge. Alternatively, the girders may be separatedinto two sections and run in until the sections have their centralportions supported in the towers and the towers rotated after thebridges 63 are removed and stored on deck. A

In raising a ship the girders may be assembled in the towers while thebarges are in port and cables used to connect the barges which may theirbe towed as a unit into position to stradle the sunken ship S and theremoored by anchors 75 ments supporting each end of the respective girdersand piping connecting the pressure elements and other piping connectingall the pressure elements at like ends of the girdersuin series. p y

4-111 a .ship salvaging apparatus, spaced oatatlon means, elevatedgirders spanning the space between the floatation means, ship hoistingmeans carried by 4said girders, leveling means supported from theiloatation means and maintaining the girders at constant heights abovethe horizon of a body of water supporting said oatation meansindependently of vertical movements of the oatation means, andpneumohydraulic weight compensating means carried by the oatation meansand supporting the ends of the girders to equalize the' extent of weightsupported by the respective girders.

5. In a ship salvaging aparatus, spaced fioatation means, elevatedgirders spanning the space between the oatation means, ship hoistingmeans carried by said girders, leveling means supported from thefioatation means and maintaining` the girders at constant heights abovethehorizon of a body of Water supporting said oatation meansindependently of vertical movements of the oatation means, andpneumohydraulic weight compensating means carried by the floatationmeans and supporting the ends of the girders to compensate the extent ofweight supported bythe respective girders, said leveling means includinghydraulic pressure elements supporting each end ofiw the respectivegirders and piping connecting the pressure elements. Y

6. In a ship salvaging apparatus, spaced floatation means, elevatedgirders spanning the space between the floatation means, shiphoistingmeans carried by said girdersp leveling means supported from theoatation means and maintaining the girders at constant heights above thehorizon of a body of water support-l ing said oatation meansindependently of vertical movements of the oatation means, andpneumohydraulic weight compensating means carried by the oatation meansand supporting the ends of the girdersto compensate the extent j ofweight supported by the respective girders,

said leveling means including hydraulic pressure elements supportingeach end of the respective girders and piping connecting the pressureelements and other piping connecting all the pressure elements at likeends of the girders in series. 2

7. In a ship salvaging apparatus, spaced iloatation means, elevatedgirders spanning the space between the oatation means, ship hoistingv'means carried by said girders, leveling means supported from theoatation means and maintaining the girders at constant heights above thehorizon-of a body of water supporting said floatation meansindependently of vertical movements of the oatation means, hoistingdrums on the oatation means each having a respective hoisting meansconnected thereto, and compensating means acting on the connectionsbetween the drums and hoisting means and compensating variations indistances between the floatation means and girders caused by wave motionand the like.

v8. In a ship salvaging apparatua, spaced 'oatation means, elevatedgirders spanning the space between the floatation means, ship hoistingmeans carried by said girders, leveling means supported from' thefloatation means and maintaining the girders at constant heights abovethe horizon of a body of water supporting said floatation meansindependently of vertical 'movements' of the fioatationmeans, -hoistingdrums on the floatation means each having a respective hoisting meansconnected thereto, and compensating means acting on the connectionsbetween the drums and hoisting meansl and compensating variations indistances between the floatation means and girders caused by wave motionand the like, said leveling means including hydraulic pressure elementssupporting each end of the respective girders and piping connecting *thepressure elements.

9. In a 'ship salvaging apparatus, spaced 75 floatation means, elevatedgirders spanning the space between the iioatation means, ship hoistingmeans carried by said girders, leveling means supported from theoatation means and tions between the drums and hoisting means andcompensating variations in distances betweenthe iloatation means andgirders caused by wave motion and the like, said leveling meansincluding hydraulic pressure elements supporting each end of therespective girders and piping connecting the pressure elements and otherpiping connecting all the pressure elements at like ends of the girdersin series.

10. In a ship salvaging apparatus, spaced iioatation means, elevatedgirders spanning the space between the floatation means, ship'hoistingmeans carried by said girders, leveling means supported from theiloatation means and maintaining the girders at constant heights abovethe horizon of a body of water supporting said iioatation meansindependently of vertical movements of the iioatation means,pneumohydraulic weight compensating means carried by the oatation meansand supporting the ends of the girders to compensate the extent ofweight supported by the respective girders, hoisting drums on theioatation means each having a respective hoisting means connectedthereto, and compensating means acting on the connections between thedrums and hoisting means vand compensating variations in distancesbetween the floatation means and girders caused by wave motion and thelike. l

11. In a ship salvaging apparatus, spaced oatation means, elevatedgirders spanning the space between the fioatation means, shipV hoistingmeans carried by said girders, leveling means supported from theoatation means and maintaining the girders at constant heights above thehorizon of a body of water supporting said iloatation meansindependently of vertical movements of the floatation means,pneumohydraulic weight compensating means carried by the iioatationmeans and supporting the ends of the girders to compensate the extent ofweight supported by the respective girders, hoisting drumson theoatation means each having a respective hoisting means connectedthereto, and compensating means acting on the connections between thedrums and hoisting means and compensating variations in distancesbetween the oatation means and girders caused by wave motion and thelike, said leveling means including hydraulic pressure elementssupporting each end of the respective girders and piping connecting thepressure elements.

12. In a ship salvaging apparatus, spaced iioatation means,elevatedgirders spanning the space between the floatation means, shiphoisting means carried by said girders, leveling means supported fromthe iloatation means/and maintaining the girders at constant heightsabove the `horizon of the body of water supporting said :lioatationmeans independently of vertical movements of the oatation means,pneumohydrauilc weight compensating means carried by the iioatationmeans and supporting the en'ds of the girders to compensate the extentof weight supported by the respective girders, hoisting drums-on theoatation means each having a respective hoisting means connectedthereto, and compensating means acting on the connections between thedrums and hoisting means and compensating variations in distancesbetween the :tloatation meansand `girders caused by wave motion and thelike, said leveling means including hydraulic pressure elementssupporting each end of the respective girders and piping connecting thepressure elements and other piping connecting all the pressure elementsat like ends of the girders in series.

13. In a ship salvaging apparatus, spaced iioatation means, elevatedgirders spanning the space between the oatation means, ship hoistingmeans carried by said girders, leveling means supported from theoatation means and maintaining the girders at constant heights above thehorizon of a body of water supporting said oatation means independentlyof vertical movements of the oatation means, and motion limiting andcheckingl means interposed between end portions oi each girder and theoatation means and arranged to permit resisted and limited longitudinalgirder movement with respect to the oatation means. y

14. In a ship salvaging apparatus, spaced iloatation means, elevatedgirders spanning the space between the iloatation means, ship hoistingmeans carried by said girders, leveling means supported from theoatation means and maintaining the girders at constant heights above thehorizon of a bod'y of water supporting said oatation means independentlyof vertical movements of the iioatation means, and motion limiting andchecking means interposed between end portions ofeach girder and the,floatation means and arranged to permit resisted and limitedlongitudinal girder movement with respect to the oatationmeans, saidleveling means including hydraulic pressure elementssupporting each endof the respective girders and piping connecting the pressure elements.

15. In a ship salvaging apparatus, spaced fioatation means, elevatedgirders spanning the by the respective girders, and motion limiting andchecking means interposed between end portions of each girder and theiioatation means andr arranged y to permit resisted and limitedlongitudinal girder movement with respect to the oatation means.

1'7. In a ship salvaging apparatus, spaced) oatation means, elevatedgirders spanning the space between the iioatation means, ship hoistingsupporting the ends of the girders to compenmeans carried by saidgirders, leveling means 'supported from the floatation means andmaintaining the girders at constant heights above the horizon of a bodyof water supporting said iioatation 4means independently of v erticalmovements of the iioatation means, pneumo-hydraulic weight compensatingmeans carried bythe oatation means and supporting the ends of thegirders to compensate the extent of weight supported by the respectivegirders, and motion limiting and checking means interposed between endportions of each girder and the oatation means and arranged to permitresisted and limited longitudinal girder movement with respect to thefloatation means, saidk leveling means in'- cluding hydraulic pressureelements supporting each end of the respective girders and pipingconnecting the pressure elements.

18. In a ship salvaging apparatus, spaced oat.- ation means, elevatedgirders spanning the space between the oatation means, ship hoistingmeans carried by said girders, leveling means supported from theiioatation means and maintaining the girders at constant heights abovethe horizon of a body of Water supporting said iioatation meansindependently of vertical movements of the oatation means,pneumo-hydraulic weight compensating means carried by the iioatationmeans and sate the extent of weight supported by the respective girders,and motion limiting and checking means interposed between end portionsof each .girder and the oatation means and arranged to permit resistedand limited longitudinal. girder movement with respect to the iioatationmeans, said leveling #means including hydraulic pressure elementssupporting each end of space between the iioatation means, ship hoistingmeans carried by said girders, leveling means supported from thefloatation means and maintaining the girders, at constant heights abovethe horizon of a body of water supporting said iioatation meanslindependently of vertical movements of the oatationmeans, andmotionlimiting and A checking means interposed between end portions 'ofeach girder and the oatation means and arranged to permit resisted andlimited longitudinal girder movement with respect to the floatationmeans, said leveling means including hydraulic pressure elementssupporting each end of the respective girders and piping connecting thepressure elements and other piping connecting all the pressure elementsat like ends ofV the girders in series.l

16. In a ship salvaging apparatus,`spaced floatation means, elevatedgirders spanning the space between the floatation means, ship hoistingmeans carried by said girders, leveling means.

supported from the oatation meansand maintaining the/girders atconstantiieights above the horizon of/a body of watersupporting saidoatation means independentlyI of vertical movements of the iioatationmeans, pneumo-hydraulic weight compensating means carried bythefloatation meansand supporting the ends of the gird' ers to compensatethextent of weight supported the respective girders and pipingconnecting the pressure elements and other piping connecting all thepressure elements at like ends of the girders in series. Y I

19. In a ship salvaging device, a spaced pair of like barges, a seriesoi spaced towers supported on each barge, carriages each slidablymounted for verticalmovement in a respective tower, hydraulicmeanscarried by said towers and supporting said carriages, girders eachhaving one 20. In a shipsalvaging devicesaced pair of like barges, aseries of spaced ers supported on each barge carriages each .slidablymounted for vertical movement in a respective tower, hydraulic meanscarriedby said towers and supporting said carriages, girders each havingone end supported in the carriage of a respective tower of one barge andits other end supported in the carriage of the corresponding tower ofthe like barges, a series. of spaced towers supported. on each barge,carriages each slidably mounted for vertical movement in a respectivetower, hydraulic means carried by said towers and sup'- porting saidcarriages, girders each having one end supported in the carriage of arespective tower oi one barge and its other end supported in thecarriage of the coresponding tower of the other barge, hoisting meanscarried by said girders and operated from said towers, and pipingconnecting certain of the hydraulic means of one barge withcorresponding hydraulic means of the other barge and connecting the saidcertain means of each barge in series, said hydraulic means includingcylinders receiving iiuid under pressure/ and plungers supporting saidgirders, the normal quantity of uid supporting the girders in midmostposition of vertical movement and the cylinders being adapted to receiveadditional fluid for moving the girders to maximum position of height inthe towers.

CARL M. ZOLL.

